Essentials for Anchored/Braced Monuments

Drilling

Need five, straight, 3.5-inch diameter, 40-45 foot long holes in the ground, one of them oriented vertically, the other four at angles of 35 degrees from vertical. The specific issues are:

The holes must be straight enough to get 1.25-inch pipe (Schedule 80; note that 1.25 "pipe" actually measures 1.66" OD) into them for the full length. If there is a likelihood of hole wander, the diameter should be increased above that given above, but it should be kept as small as possible to minimize the amount of grout needed.
The intersection of the five pipes should be at a single point (where the monument will go); this may be at or above the ground surface, depending on where the mark is wanted. The drill rig must be able to make small adjustments in hole location and angle to meet this specification. The drilling angle can be from 30 to 40 degrees.

We have, with one exception, used a compressed-air ``crawler'' drill rig, designed for drilling shot holes at construction sites (or for open-pit mines). Other types could be used; the important thing is that the rig be able to drill into whatever material is present, and be manuverable (though you can always take more time with a less maneuverable rig).

Construction Supplies and Materials

The amounts given are for one hole; the total required should thus be by multiplied by 5.

Refrigeration insulation, 0.75-inch thick; this comes in tubes and is taped around item 2 using longitudinal strips of strapping tape. It is then covered with duct tape.
15-foot length of schedule 40 2.5 inch belled-end PVC pipe.
50 feet of schedule-80 1.25-inch galvanized pipe; this comes in 20-foot sections, which are joined with 1.25-inch schedule-80 (2-inch OD; thin-walled) couplings.
50 feet of 0.5-inch rebar.
Enough grout (cement, sand, and water only - no rock) to completely fill the hole to the surface. This should be an expansive grout; regular grout might do but is not good because it will shrink on drying. Concrete cannot be used because the rock component makes it impossible to pour down the pipes.
Centralizer for bottom section of pipe (this is home-made).
Blowout tube for cleaning hole: 60 feet of 1.25-inch schedule-40 PVC (comes in 20-foot sections, and is assembled, with couplings and PVC glue on site, used and then discarded).
Fitting to attach to pipe on which antenna can be mounted (also home-made).

Construction Tools and Equipment

This is a partial list of the major tools and other items needed for construction; some of these can either be reused, or will be only partly used up.

Cement mixer (you do not want to mix this amount of grout by hand if at all possible).
Compressed air supply with fittings to attach to a blowout tube.
Water for mixing with grout;
Pipe-joint compound, grease, Teflon tape, PVC cement.
Duct tape and strapping tape for attaching insulation around top PVC.
Inclinometer for setting drill angle.
Welding equipment to weld pipes together at intersection; this takes a few hours at most.

In addition, a good supply of general-purpose tools (eg. shovels and hammers) should be available.

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